Synthesis and Reactivity of (NHC)Au^I–Mercaptopyridine Complexes

Abstract

Reaction of (NHC)­Au–X (X = halide) complexes with 2- or 4-mercaptopyridine under basic conditions allows for the preparation of a series of (NHC)­AuI–mercaptopyridine complexes 1–4 in high yields. All complexes have been fully characterized by means of 1H and 13C NMR spectroscopy, melting point, and elemental analysis. Single crystals of complexes 1–3 were obtained, and the solid-state structures display a linear Au­(I) center with coordination to the NHC ligand and the sulfur atom of the mercaptopyridine moiety. Interestingly, weak γ-anagostic C–H···Au interactions are found in complexes 1–3 regardless of the relative N or S position in the mercaptopyridine. Taking advantage of the free pyridine nitrogen, reaction of complexes 1 and 2 with palladium allyl chloride dimer permits the isolation of heteronuclear Au/Pd complexes 5 and 8 featuring a bridging ambidentate mercaptopyridine ligand. Further reactivity of complexes 1–3 toward B­(C6F5)3 produces complexes 6, 7, and 9, which display frustrated Lewis pair reactivity with the activation of a H–F bond.

Synthesis of Heterobimetallic Gold(I) Palladium(II) Bis(acyclic diaminocarbene) Complexes via the Isonitrile Route

“…Heterobimetallic complexes represent a vast and growing substance class in both coordination and organometallic chemistry, in which early as well as late transition metals are applied. − Therein, either direct metal–metal bonds − or various anionic or neutral bridging ligands − are employed that enable applications in catalysis − and medicinal chemistry. − Diaminocarbene metal complexes − represent a prominent substance class in organometallic chemistry, serving as metallapharmaceutical agents − or catalysts. − Although several homo- − as well as heterodinuclear complexes , bearing diaminocarbenes are known, only a limited number of heterodinuclear diaminocarbene gold complexes − can be found in the literature.…”

Donor Strength Determination of Anionic Ligands

“…To study this feasibility, gold­(I) complexes of 1,3-(2,6-diisopropylphenyl)­imidazolin-2-ylidene (IPr) as one of the most popular NHCs were chosen. Relevant data ,− for eight anions obtained in CDCl 3 were found suitable and subjected to the correlation study (see Supporting Information, Table S3). The graphical plot depicted in Figure reveals a similar excellent correlation with a R 2 value of 0.9954 between the chemical shifts of the carbene donors in [AuX­(IPr)] and [AuX­( i Pr 2 -bimy)] complexes, respectively.…”

Heteroleptic Silver(I) and Gold(I) N-Heterocyclic Carbene Complexes: Structural Characterization, Computational Analysis, Tyrosinase Inhibitory, and Biological Effects

“…The Au1−S1 bond distance of 2.304(3) Å confirms a covalent bonding consistent with the previously values in reported Au−S bonds in (NHC)Au-mercaptopyridine complexes. 54 Both the Au1−C7 and Au1−S1 bond distances in 2 are shorter than those for the silver carbene complex 1, pointing to a stronger covalent bonding between gold and ligands with C and S donor atoms. The second phosphorus− sulfur bond does not participate in bonding with the metal center; therefore, it retains its double bond character.…”